1. Field of Invention
The invention discloses novel fatty carboxylic acid salts of organofunctional silicone useful in the preparation of a variety of personal care formulations. The products are the fatty carboxylic acid salts of silicone polymers which contain amino pendant functionality. Compounds of the invention deposit on the surface of various substrates, like hair and skin. Thereby altering the surface properties. The properties which can be given to substrates include; softness, lubrication and hydrophobicity. The compounds of the present invention function as humectants and protective barriers on the skin. Additionally, they impart a high level of sheen and softness to the skin. The compounds of the present invention can also be used as partial or total substitute for petrolatum. Another surprising aspect of the compounds of the present invention is their lack of irritation and toxicity when applied to eyes and skin. They are alos non comedogenic.
The compounds of the present invention are prepared by the complete neutralization of a silicone amine with a fatty carboxylic acid. The compounds of the present invention, in stark contrast to fatty amine derivatives, show no irritation to skin and no oral toxicity when tested at 5.0 gms/kg body weight.
2. Description of the Arts and Practices
Silicone compounds have been known to be active at the surface of hair and skin. Silicone oils make good lubricants and are very stable to oxidation, however, their high cost and lack of efficiency at low concentrations as well as low durability have made their acceptance in commercial products quite low. In all instances, commercially available quats are the active ingredient in traditional laundry care markets, with little or no silicone added.
The low efficiency and low durability of dimethylpolysiloxane is due to the fact that it is very water insoluble and deposits on the surface to obtain a minimum free energy in the solution. Simply, the silicone oil delivery is to the surface by hydrophobic binding, not chemical bonding. At the surface, the dimethylpolysiloxane is a very effective lubricant, however, there are two drawbacks, first; the dimethylpolysiloxane is not chemically bonded so the effect is very transient and disappears with one washing, and second; since there is no reaction of the dimethylpolysiloxane to the surface an equilibrium between fiber absorbed dimethylpolysiloxane and dimethylpolysiloxane in the dispersion results in very inefficient percentage of silicone deposited. A large amount of the expensive silicone goes down the drain with the waste water.
One major area in which the compounds of the present invention find applications is in so called two in one shampoos. That is shampoo compositions which also condition and soften. Soiled human hair is shampooed to remove sebum that is naturally secreted by the head, as well as soil and other atmospheric contaminants that accumulate on the hair. Sebum accumulates on the hair in a short time, leaving the hair with a greasy, dirty feel and poor manageability. The most effective shampoos for cleansing the hair and for the removal of the atmospheric contaminants and sebum, are those that contain high lather anionic detergents, such as the long chain alkyl sulfates or ethoxylated long chain alkyl sulfates. These anionic detergents are very effective for cleansing the hair but after rinsing with water, leave a the hair in a condition often called "creak". In this condition the hair is likley to become extremely tangled, unmanageable and cosmetically unappealing.
Thoroughly cleansed hair, which is stripped of natural oils, is extremely difficult to comb in either the wet or dry state because the individual hair fibers tend to snarl, kink, and interlock with each other. Particularly prior to complete drying of thoroughly cleansed hair, the hair is very difficult to comb, brush or manage. This is refferred to as poor wet combability. Even after complete drying, the thoroughly cleansed hair remains difficult to comb or brush and does not set well. Additionally, thoroughly clean, dried hair also has undesirable electrostatic properties in a low humidity atmosphere that causes the hair to "fly away", thereby further reducing the combing or brushing property of the hair.
After shampoo hair conditioning compositions have been used for many years. One of the problems with such a conditioner is that they commonly contain large quantities of fatty quaternaries which are irritating to the eyes, build up on the hair and cause other problems with altering the feel and appearance of the hair. Some fatty quaternary compounds are known to be toxic to aquatic organisms. In addition this approach entails an additional step which is time consuming.
An approach toward eliminating the time consuming problem with after shampooing conditioners has been the preparation of a conditioning shampoo. While several products have been on the market, there has been some major difficults encountered. One major problem has been incompatibility of the shampoo composition due in large part to incompatability between anionic surfactants and the fatty cationic compounds which are the conditioning agents commonly used. Contact between an anionic surfactant and a cationic surfactant produces a precipitate that forms immediately and significantly reduces the cleaning and conditioning properties. Another problem has been the reduction in cleansing and conditioning effectiveness. This can occur even when the incompatability problems have been overcome by modification of the formulation. This incompatibility between an anionic surfactant and a cationic conditioning compound is well recognized by those skilled in the art. For example, Sagarin in Cosmetics, Interscience Publishers, Inc., New York, p. 538 (1957), states that anionic and cationic compounds cannot be used in combination because they react to form insoluble salts. As will be shown, the present compositions make use of a complex which not only is soluble, but is conditioning and emulsifying for insoluble silicone. One of the reasons for this being a surprising discovery is that the above mentioned literature references teach away from the present invention. Other novel aspects of the present compositions and processes for their use will become clear by reading the rest of the disclosure.
Another attempt to overcome the incompatibility problem in the formulation of conditioning products is exemplified by the following patents that disclose compositions containing surfactants that are not anionic, specifically nonionics, amphoterics and zwitterionics surfactants can be formulated into a conditioning composition. Examples of this type of product is shown in the following patents; U.S. Pat. No. 3,849,348 to Hewitt; U.S. Pat. No. 3,990,991 to Gerstein; and U.S. Pat. No. 3,822,312 to Sato. Compositions based upon these alternate surfactant types do not have the detergent properties needed for successful shampoos and have enjoyed minimal commercial success.
Another attempt to overcome the instability problem encountered using cationic and anionic surfactants has been to replace the fatty quaternary compound in the composition with a non-fatty water insoluble conditioning agent such as the nonvolatile silicones. This approach has become well recognized in the art as providing a degree of softness to the hair. The formulation of the so called two in one shampoo (also known as shampoo plus conditioner) has been attempted in recent years. Many of these compositions contain highly insoluble silicones and consequently require elaborate formulation additives to thicken and otherwise hold the compositions together. The result is inferior preformance, due in part to lack of homogenity of the compositions. It is not uncommon to see the insoluble silicone floating on the top of a bottle of two in one shampoo. These formulation additives which increase stability, also have a negative effect upon performance of the composition.
Many attempts have bene made over the years to product a truly stable conditioner compostion having a dispersed, insoluble, nonvolatile silicone material suspended therein, while retaining the cleansing and conditioning performance of the conditioning shampoo. This stability problem is particularly prevalent in conditioning products containing an anionic surfactant and a cationic conditioning material which, as outlined above, by themselves tend to interact and present stability problems. A variety of materials have been proposed for inclusion in silicone containing conditioners for purposed of thickening and stabilization, such as xanthan gum, long chain acyl derivatives, long chain amide oxides, and long chain alkanolamides as disclosed in U.S. Pat. Nos. 4,788,006; 4,704,272; and 4,741,855. The effect of incorporating thickening agents and other stabilizers is a greasy unappealing feeling on the hair and a greasy build up on repeated use.
Silicones added to shampoo compositions have been known for many years. Several examples are the following U.S. patents: U.S. Pat. No. 2,826,551 issued Mar. 11, 1958 to Green; U.S. Pat. No. 3,964,500 issued Jun. 22, 1976 to Drakoff; U.S. Pat. No. 4,364,837 issued Dec. 21, 1982 to Pader; British Pat. No. 849,433, issued Sep. 28, 1960 to Woolston; U.S. Pat. No. 4,741,855, to Grote, et al.; U.S. Pat. Nos. 4,788,006 and 4,902,499 to Bolich, Jr. et al. and U.S. Pat. No. 4,704,272 to Oh, et al. The diversity of approach used by the various inventors and the extended time frame over which work has been attempted, demonstrates a long felt, and unfulfilled need for a truly functional conditioning product.
U.S. Pat. No. 5,034,218 issued July 1991 to Duvel teaches that conditioning shampoo compositions can be prepared using non volatile silicone compounds and a variety of surfactants, fatty quaternary compounds, fatty alcohols, and polymeric suspending agents. The need for all these components to make a stable or metastable composition is common in the preparation of conditioning products. This type of formulation is appreciably different from the compositions of the present invention in that the present compositions are conditioners which are anhydrous systems rather than aqueous emulsions or thickened dispersions additionally, the present compositions do not contain many of the fatty materials which aside from building up on hair are known to be irritating to eye and skin.
One approach to overcome the undesirable effects of either post treatment with an insoluble fatty quaternary or fatty alcohol containing conditioners, or the incorporation of silicone into a thick stabilized shampoo is to pre-treat the hair with a water soluble quaternary. U.S. Pat. No. 4,061,150 issued Dec. 6, 1977 to Dasher et al, teaches that dilute aqueous water soluble fatty quaternary compounds can be used to precondition hair before shampooing. This technology, while representing a significant advance over the art practiced before it, did not provide the advantages of silicone products offered by the present invention.
One major problem which is encountered formulating with silicone compounds is the selection of solvents in which the silicone oil is placed. Silicone oils are insoluble in mineral oil, water, most protic solvents and many other solvents. Most are soluble in mineral spirits which is volatile and limits the ability to formulate personal care products. Many attempts have been made to formulate silicone products which are useful in a variety of solvents.
Many attempts have been made to overcome these problems and get a truly substantive product, which deposits efficiently. One approach has been to use hydrosilation technology to make alkoxylated silicone polymers, used as raw materials in this invention. These materials do not have the substantivity desired to make them suitable for use as antistats, softeners and or soil release agents. Hydrosilation technology is known to those skilled in the art and is outlined in U.S. Pat. No. 4,083,856. These materials, prepared by the hydrosilation of a vinyl alkoxylated alcohol and a silanic hydrogen containing polymer, by virtue of their alkoxylation, exhibit a high cloud point classically seen in nonionics, which is a point were at some elevated temperature, the silicone polymer comes out of solution and becomes more substantive to the hydrophobic substrate. This approach allows for better efficiencies but does little if anything for long term substantivity.
U.S. Pat. No. 3,511,699 to Sterman issued May 12, 1970 teaches that epoxy compounds placed in the silicone backbone by hydrosilation can be cured onto certain fibers to give improved substantivity. The substantivity is based upon the reaction of hydroxyl groups on the cellulosic and the epoxy group in the silicone polymer. The resulting bond is an ether linkage and a new hydroxyl group. While a definite improvement over earlier compounds the efficiency and durability of these compounds are not enough to allow for cost effective incorporation of these materials in detergent formulations.
U.S. Pat. No. 4,960,845 to O'Lenick issued October 1990 discloses sulfated silicone polymers which are high foaming surfactants.
U.S. Pat. No. 4,973,643 to O'Lenick issued November 1990 discloses ether amine compounds useful as raw materials in the preparation of the compounds of the present invention.
U.S. Pat. No. 3,801,572 to Berger issued April 1974 discloses amino silicones suitable as raw materials in the present invention.
U.S. Pat. No. 4,785,067 to Brumbill issued in 1988, discloses a partially neutralized, partially free amine, carboxylic acid salt for use as a protective coating and rust preventative.